Glab. perennial herb up to 1 m. or more tall, with long taproot; stock c. 1 cm. diam.; stems up to 1 cm. diam., erect to spreading, branching at a wide angle. Lvs up to c. 15 cm. long, thin, oblong to lanceolate in outline, subacute to acuminate, cuneately narrowed into amplexicaul base; coarsely and irregularly serrate (rarely subentire) to lyrately pinnatifid. Racemes simple or sparingly branched, up to c. 5 dm. long; pedicels sub- patent, c. 5 mm. long. Sepals ovate-oblong, ± 3 mm. long; petals white, linear-spathulate, ± 3·5 mm. long. Siliques 3 × 1-1·5 cm., spreading; styles stout, c. 2 mm. long. Seeds c. 1 × 0.75 mm., reticulate-papillose, reddish brown.